From your picture, the left-most white ring is in the wrong place. Lift it out of the groove below the threads and slide it down over the black o-ring. It should be resting on the pocket clip, between the pocket clip and the black o-ring.

When you screw on the cap, the white o-ring presses against the clip and prevents it from rotating.

The second white o-ring in the right of the picture is meant to help keep the black inner tube centered and reduce the chance of a short between the inner tube and the switch. However, sometimes it can cause problems. If your light isn’t working right, you might try removing that o-ring completely and see if it works without it.

I don’t think anyone really knows. It’s not for moisture and it’s not needed to prevent a short circuit. I don’t think it’s needed for centering the tube. It may provide a bit a tolerance and pressure to keep the center tube pressed against the tail switch.

It may be to prevent the inner tube from rotating. If it’s not there, the metal lip will press against the outer battery tube. Then if it twists it can wear the anodized finish and create a switch short. Just a theory.

The other white o-ring is just to keep the clip steady. For some lights it can prevent the tail cap from fully tightening.

Firelight2 Thank you very much for the clarification. I did everything as you said and everything turned out, the flashlight works, the tail is tightened, the clip for the pocket does not rotate. Everything is fine. Apparently I have a flashlight from the latest releases and the board in the shank is tightened with a threaded nut, this is very convenient, since nothing falls out when disassembling.

I received 2 x FW3a and 1 x FW1A today.
I cannot for the life of me remove the tailcap off two of the lights. Ive ripped holes in a bath towel, used pliers, rubber and hurt my hands.
I want to replace the battery tube with smaller tubes and remove the stock clip, this is my right. They shouldnt be tightening this thing so far its basically welded just because they cant design a proper light.
I know what im doing, let me do it. One of the switches also doesnt feel right and is causing it to not register clicks, i want to fix it.

None of my FW3 series lights have glued tailcaps. Some of them were screwed pretty hard together, but nothing I couldn’t unscrew by hand after applying some 3M indoor stairway grip tape to for extra grip.

In addition to my stuck caps, my 1 day old FW3A XPL 5k is broken from the factory.
It was flickering from the first use a little and when it got hot the tint went extremely blue.
I removed the lens and i can see the LEDPCB is floating free from the driver and the negative wire isnt soldered properly, in fact its come off.
I dont even have a working Soldering Iron at the moment due to Covid-19 shipping issues, been waiting 6 weeks

How is the LED board meant to sit in the head? Does it sit in a thread? Or is it just held onto the driver with thermal paste and pressure from above?
No doubt the board wasnt removing any heat into the body and it was causing the light to go blue under extreme heat, possibly desoldering the wire with it.
If i had an iron id be happy to reattach it, but if its part of a bigger issue of a free floating PCB i will send it back or something, along with the stuck tail cap!

Later model FW3 series lights also have a small screw that sits in a divot on the underside of the star to keep the star from rotating when the bezel is screwed on. The latest models are the same, but have an extra-thick copper star.

If the star isn’t aligned properly during assembly, the screw head on the shelf meant to sit in the divot on the bottom of the star might not be in the divot. If that happens, the screw head will keep the entire bottom of the star from sitting flat on the shelf. This could result in the star overheating and the driver wire desoldering itself like you observed.

The fix is fairly straightforward, but unfortunately does require a soldering iron. You will need to align the star and resolder the driver wire. Preferably after removing it completely and applying fresh thermal grease.

I’m not sure why you can’t remove the tailcaps on your lights though. Until your post I’ve never heard of any FW3 lights having glued tailcaps. They tighten them a lot in the latest batches because that’s what’s necessary for reliable operation. But they certainly aren’t welded and with some grip assistance you should easily be able to unscrew them.

It was flickering from the first use a little and when it got hot the tint went extremely blue.

I removed the lens and i can see the LEDPCB is floating free from the driver and the negative wire isnt soldered properly, in fact its come off.

How is the LED board meant to sit in the head? Does it sit in a thread? Or is it just held onto the driver with thermal paste and pressure from above?
No doubt the board wasnt removing any heat into the body and it was causing the light to go blue under extreme heat, possibly desoldering the wire with it.
If i had an iron id be happy to reattach it, but if its part of a bigger issue of a free floating PCB i will send it back or something, along with the stuck tail cap!

I doubt the flickering is related. That is usually due to a contact problem with the head not being tight enough or the battery length being wrong, etc…

The leds are soldered to the MCPCB (metal core printed circuit board). The MCPCB is pressed against the metal shelf machined into the head. The driver is on the other side of the shelf next to the battery. The tir lens and threaded bezel push the mcpcb against the shelf.

The led turning blue definitely sounds like it got overheated and that unsoldered the wire. Why, I’m not sure. I assume the bezel was tight and putting pressure on the MCPCB. It’s possible there is a piece of debris (maybe tiny solder blob) or maybe a metal burr under the MCPCB preventing it from sitting flat.

Shipping it back typically costs more than the light (a small insured package is about $40 USD from USA to China) so I doubt you or they would want to spend that kind of money. Typically they would just send you a new one and you keep the defective one.

Later model FW3 series lights also have a small screw that sits in a divot on the underside of the star to keep the star from rotating when the bezel is screwed on. The latest models are the same, but have an extra-thick copper star.

If the star isn’t aligned properly during assembly, the screw head on the shelf meant to sit in the divot on the bottom of the star might not be in the divot. If that happens, the screw head will keep the entire bottom of the star from sitting flat on the shelf. This could result in the star overheating and the driver wire desoldering itself like you observed.

The fix is fairly straightforward, but unfortunately does require a soldering iron. You will need to align the star and resolder the driver wire. Preferably after removing it completely and applying fresh thermal grease.

I’m not sure why you can’t remove the tailcaps on your lights though. Until your post I’ve never heard of any FW3 lights having glued tailcaps. They tighten them a lot in the latest batches because that’s what’s necessary for reliable operation. But they certainly aren’t welded and with some grip assistance you should easily be able to unscrew them.

Oh yeah, I forget about the newer ones having that design change. If the MCPCB was sitting on top of the screw wouldn’t it sit really high and the bezel have a noticeable gap near the threads?

There’s no need to replace the thermal grease. It may not have even been spread out yet.

Thanks guys.
With that info i believe there is something under the MCPCB, no way i can get it sitting flat on its own. Also feels very dry underneath pushing it around, but it could be a symptom of the foreign mass.
Ill get in touch with Neal. A new light would solve both my issues, i can deal with one stuck tailcap if the others are all ok, as much as it puts a damper on my “lego games”, bound to have atleast one 18650 version of my lights at any given time.

Edit. Thermal paste is not an issue for me, 20 years of overclocking im well versed and stocked

I have 2 FW3A SST20 new, was playing with them right out the box, and noticed that in lockout mode, a double click would activate a slightly higher mode, than the standard moonlight. Cool and useful, read that it’s a feature added to the firmware.

Then I went to ramp config and reconfigured to the factory standards (Floor N = 1 and Ceiling N = 21), just to make sure they were configured correctly.

And this double click higher mode in lockout disappeared from both flashlights after this reconfig. I want it back!

The Anduril version is not so new, I can’t check it, doesn’t factory reset with 13 clicks.

I have 2 FW3A SST20 new, was playing with them right out the box, and noticed that in lockout mode, a double click would activate a slightly higher mode, than the standard moonlight. Cool and useful, read that it’s a feature added to the firmware.

Then I went to ramp config and reconfigured to the factory standards (Floor N = 1 and Ceiling N = 21), just to make sure they were configured correctly.

And this double click higher mode in lockout disappeared from both flashlights after this reconfig. I want it back!

The Anduril version is not so new, I can’t check it, doesn’t factory reset with 13 clicks.

I have 2 FW3A SST20 new, was playing with them right out the box, and noticed that in lockout mode, a double click would activate a slightly higher mode, than the standard moonlight. Cool and useful, read that it’s a feature added to the firmware.

Then I went to ramp config and reconfigured to the factory standards (Floor N = 1 and Ceiling N = 21), just to make sure they were configured correctly.

And this double click higher mode in lockout disappeared from both flashlights after this reconfig. I want it back!

The Anduril version is not so new, I can’t check it, doesn’t factory reset with 13 clicks.

Is it a bug?

My understanding is the double-click while in lockout swaps between the floors set for ramped and stepped modes.

It’s possible you just set them both to the same value. If that’s the case, then double-clicking while in lockout does nothing.

The voltage shown by BattCheck seems to indicate higher…. Also, what does 4.0V from BattCheck mean? Does it mean like between 3.95V and 4.04V (rounded to the nearest tenth)? If so, 3.87V should show 3.9V.

Not sure about the FW’s, but on my D4S it blinks out 3.9 from 3.99 down to 3.90 and changes to 3.8 at 3.89. Might just be that one light, can’t really say.

My D18 seems to be more accurate. So, I was just curious about the others.

They all vary to a certain degree. The same is true for NarsilM lights. I don’t think the voltage detection part of the Atiny85 is all that accurate. It’s a 15 year old design.

Each chip is consistent, though. You can rewrite the code and reflash the firmware with a correction factor to make the voltage readout very accurate. This obviously can’t be done in mass production so we are stuck with what we have.

ToyKeeper wrote:

I mostly just decided I was okay with a precision of +/- ~0.15V, since it’s not easy to get a mass-produced attiny device to measure more accurately than that…

i see 4.1 a lot and 3.9 – does it just skip 4.0 to avoid ambiguity in the flashing (ie how can you tell it is flashing ‘zero times’?)

wle

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